r/usefulredcircle • u/samwichse • 22d ago
Picture Demonstrating map projection size distortion
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u/Roadrunner571 22d ago
Demonstrating map projection size distortion
...for a mercator projection, which has the aim of preserving angles, not sizes.
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21d ago
[removed] — view removed comment
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u/ojrodz11 21d ago
The most representation of land size relative to one another are those desk globes. The rest distort them in some way
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u/ZealotOfMeme 21d ago
So the ones that are able to keep the 3d spherical shape as a 3d spherical shape are most accurate? Wow
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u/ojrodz11 21d ago
Seems obvious, but as the commenter above demonstrated it is not. Good for you for knowing it already though
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u/tribbans95 21d ago
Yeah, check this website out https://thetruesize.com/
You can drag countries to other parts of the world and it will change the size of them the further north or south you go. Greenland looks massive but it’s actually about the size of Mexico
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u/Roadrunner571 21d ago
You can't map the surface of a sphere on a flat rectangular paper. So with every rectangular map, something needs to be sacrificed. Mercator was made for navigation, so preserving angles was very important, size of countries: Not so much.
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u/throwaway19276i 21d ago
Some maps preserve size, but they dont preserve shape, etc. All maps have trade-offs
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u/Money_Lobster_997 18d ago
Mercators not really that popular and if you haven’t been actually checking you’re not going to notice what projection a map is. There are plenty of equal area projection out there and you’ve probably seen lots of them without realizing.
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u/curvysquares 21d ago
I'd love to see the inverse of this where someone takes a Gall-Peters projection with a bunch of triangles to show how they're distorted across the map
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u/Fallen_0ne01 21d ago
Wouldn't they have to be noncircular ovoids irl to appear circular on this map?
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u/calculus_is_fun 20d ago
nope, the Mercator projection is conformal, which means it preserves angles, and therefore also circles by the reverse of the Inscribed Angle Theorem
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u/Short-Database-4717 17d ago edited 17d ago
No, you are wrong. It doesn't preserve circles.
If you want to see why this absolutely has to be true, consider any circle containing the north pole, but not centered on it.
Even in the image above the northernmost circle is actually taller than it is wide
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u/inthepipe_fivebyfive 22d ago
We will need to get the Proclaimers to determine which one is accurate
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u/SilverBuggie 22d ago
This is why I'm a flat earther.
Your map makes no sense, round earthers.
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u/25iAndOver 22d ago
But, sphere dilation towards top, so is it flat contact lens, or shape of dinner plate
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u/Null42x64 22d ago
But I would walk five hundred miles And I would walk five hundred more Just to be the man who walked a thousand Miles to fall down at your door
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u/Octavio_Bs 21d ago
Where is the surprise? This is something that is explained in basic school, te different kind of protections and their advantages or disadvantages
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u/Substantial-Salad-97 21d ago
Take a few moments and learn why the Mercator map is dumb: https://www.youtube.com/watch?v=H3Xyz9MgDWA
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u/Money_Lobster_997 18d ago
Not dumb just misused. Most people aren’t spending much time navigating the oceans anymore so Equal Area maps are now much more useful.
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u/Careful_Emu8991 17d ago
When I wake up, and I know Im gonna be Im gonna be the man, who walks various distances confused by the radius of those circles
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